1. Field
Embodiments of the present invention relate to an optical sensor embeddable in a display device using transverse Fabry-Perot resonator as detectors.
2. Related Art
Display devices have become increasingly popular and are widely used, such as in cell phones, computer monitors, televisions, tablets, etc. These display devices may be any suitable type (kind) of display, including an organic light emitting display (OLED), a liquid crystal display (LCD), etc. In particular, display devices including optical sensors have been developed to, for example, detect a user's interaction with the display device (e.g., an interaction with the display device via the user's finger or via use of a stylus), sense ambient light, scan documents, scan finger print, etc.
In the realm of touch enabled display systems, the approach of the related art is to physically bond a touch panel over the display device. However, bonding a touch panel reduces display performance parameters, such as contrast ratio and light throughput, and adds thickness and weight to the display system. Further, capacitive in-cell touch solutions, which are often employed in touch panels, have significant yield and noise handling issues, resulting in increased manufacturing costs.
Solutions exist for embedding optical sensing arrays; however, these related art solutions tend to suffer from a number of shortcomings. For example, related art embedded optical sensors offer little to no sensing wavelength selection, which results in low signal to noise ratio under normal ambient lighting conditions. The optical sensors generally absorb a broad spectrum of light rather than being sensitive to only a narrow band of light. This may necessitate using optical filters, which may be very expensive and, in some applications, may not even be feasible due to structural limitations. Further, given the difficulty of integrating optical filters, existing embedded solutions offer very limited imaging capability. Related art sensors have little to no angular selectivity, which limits their use to situations in which sensing light is collimated, making them impractical in most cases. Additionally, related art embedded sensors exhibit low light detection efficiency. To increase the detection efficiency, the thickness of the light sensing material may be increased, which adversely affects the response time and may be expensive.
What is desired is an inexpensive embedded optical sensor that offers high angular and wavelength selectivity as well as detection efficiency, without the need for optical lenses or filters.